One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10)(11,24)(12,18)(13,19)(14,34)(15,22)(16,23)(17,26)(20,33)(21,36)(25,37)(27,29)(28,35)(30,32)(31,40)(38,39) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,11,15,26,16,28,36,27)(10,17,21,24,23,29,22,35)(12,25,30,20,31,34,38,19)(13,32,14,18,33,39,37,40)(2,6)(3,7)(9,12)(10,18)(11,25)(13,29)(14,35)(15,30)(16,31)(17,33)(19,27)(20,26)(21,39)(22,32)(23,40)(24,37)(28,34)(36,38) involution — undirected(2,6)(5,8)(9,13,15,14,16,33,36,37)(10,19,22,34,23,20,21,25)(11,18,27,32,28,40,26,39)(12,29,30,35,31,17,38,24)(9,14,36,13,16,37,15,33)(10,20,22,25,23,19,21,34)(11,18,27,32,28,40,26,39)(12,24,38,17,31,35,30,29)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.